The term automobile means all kind of textile component e.g. fibers, filament, yarn and fabric used in transportation like cars, train, buses, air planes and marine vehicles. Over 15-20 different kinds of fabric are used in automobiles. Automotive textiles are engineered fabrics to meet the challenges of an increasingly competitive automobile manufacturer requirement. Textiles provide a means of decoration and a warm soft touch to the seats and the interior of the car, but they are also used in more functional applications. The automobile industry is the largest user of technical textiles, with about 20 kg in each of the 45 million or so cars made every year world-wide. The automobile industry has started in the late 1950s to research on air bags and the first invented version was patented on 1953. Then, Air bags have been commercially available since late 1980s. The technological difficulty leads to the 30-year span between the first patent and the common availability of the airbags. Air bags have even been suggested for protection of the head. Rear passenger airbags are being developed as well as side airbags which provide protection in roll-over accidents by shielding the occupants from side window glass and protecting the head.
A recent study shows that there is a significantly higher reduction in moderate to serious head injuries for people using airbags and seat belts together than for people using only seat belts, when compared to drivers using no restraining safety equipment. The study also says that deaths among drivers using both air bags and seat belts are 26% lower than among drivers using seat belts alone. Airbag market is growing very rapidly in the Western Europe and in USA and become that airbag is mandatory in the newly produced cars. They are designed to act as the supplemental safety device in addition to the seat belts.
Objectiveof Airbag
Themain objective of an air bag is to lower the number of injuries by reducing thefore exerted by steering wheel and the dashboard or any point on the body. Thisis accomplished in two ways:
- By increasing the interval over the force being applied
- By spreading the fore over a large area of the body
The air bag system has been engineered to work with the pressure between the passenger and steering wheel, in a fraction of second. The airbag unit must also stay intact at low velocity collisions. The crash sensor, which detects the collisions and trigger the bag, to inflate must take all those constraints into account. The operation of deflation happens when N2 generation stops, gas molecules escape the bag through vents. The pressure inside the bag decrease sand the bag deflates slightly to create a soft cushion. By 2 seconds after the initial impact, the pressure inside the bag has reached atmospheric pressure.